The "midst" of something in the Bible represents the thing that is most central and most important to the spiritual state being described, the motivation that drives everything else. In general this will be something we love or feel, because at the core of things we are what we love; our loves define us.

(References: Apocalypse Revealed 44, 90, 268; Arcana Coelestia 2252, 2940, 10153, 10365, 10557, 10635, 10641)

3338. In addition to those two forms of light there are also two forms of warmth or heat, which likewise have two separate sources. The warmth of heaven comes from the Sun of heaven, which is the Lord, and the warmth of the world comes from the sun of the world, which is plainly visible before our eyes. The warmth of heaven manifests itself before the internal man by means of spiritual loves and affections, whereas the warmth of the world manifests itself before the external man by means of natural loves and affections. The first form of warmth constitutes the life of the internal man, whereas the second constitutes that of the external man; for without love and affection a person cannot live at all. Between those two forms of warmth also correspondences exist. Those two forms of it become loves and affections from the influx of the Lord's life, and therefore they show themselves to man as if they were not forms of warmth, when in fact that is what they are. For if a person did not receive warmth from the Lord's inflowing life, both in his internal man and in his external man, he would instantly fall down dead. These considerations are evident to anyone from the fact that to the extent a person is fired by love he also becomes warmer, and to the extent love departs he cools off. It is from this warmth that a person's will lives, but from the light spoken of above that his understanding lives.